Image quality of image data generated by digital still cameras (DSC), digital video cameras (DVC), scanners, and the like, can be adjusted at one's discretion by image retouch applications on personal computers. The image adjustment function for automatic adjustment of image quality of image data is typically provided in image retouch applications, and the image quality of image data output from an output device can be easily improved if this image adjustment function is used. Well-known examples of output devices for image files include CRT, LCD, printers, projectors, TV receivers, and the like.
Printer drivers controlling the operation of printers, which are the output devices, are also provided with the function of automatic adjustment of image quality of image data, and the image quality of image data which is to be printed can be also easily improved by using such printer drivers.
However, with the image quality automatic adjustment function provided by such image retouch applications and printer drivers, image quality correction is conducted by using as a standard the image data having typical image quality characteristic. By contrast, image data which are the object of image processing can be generated under a variety of different conditions. Therefore, image quality sometimes cannot be improved by executing indiscriminately the image quality automatic adjustment function and changing the image quality parameter values of image data by using the standard values.
Further, in some of image data generation devices, such as DSC and the like, image quality of image data can be adjusted at one's discretion during image data generation, and the user can intentionally generate image data with the prescribed image quality. When the image quality automatic adjustment function is executed with respect to such image data, the problem is that the adjustment is automatically conducted based on the image quality serving as a standard till the intended image quality of the image data, and automatic image adjustment reflecting the user's intention cannot be executed. This problem is not limited to DSC and is a common problem for other image data generation devices such as DVC and the like.